Covering a large space at 360 degrees, without echo

Where echo comes from in a large volume

From a direct sound followed by delayed reflections off distant surfaces. The larger the volume, the longer the delay, and beyond a certain threshold the ear no longer merges the two: it hears two events instead of one.

Why adding speakers sometimes makes it worse

Two sources several metres apart reach a listener with an offset. That offset produces a loss of intelligibility corrected by electronic delays, which calls for a study and careful commissioning.

What an omnidirectional source changes

A single source radiating through three hundred and sixty degrees covers a wide perimeter without introducing an offset between sources, since there is only one. That is an advantage of principle in an open room.

The central position

An omnidirectional source gives its best result at the centre of the area to cover, at height, clear of nearby obstacles. The constraint concerns the fixing point rather than the orientation.

What still has to be dealt with

Absorption. A very reverberant room will stay very reverberant whatever the source, and treating the walls or the ceiling acts on the cause where the source acts only on the distribution.

How to check before investing

A hand clap at the centre of the room. If the sound comes back clearly separated, the space needs acoustic treatment before any choice of equipment, and that listening takes three seconds. No sound system quotation should be drawn up without someone having made that gesture in the room.

Ceiling absorption is developed on the R'Acoustic 20 page, and the product on its page.